From db8109a8bb4a4b31e7f630d7667749d62ee4a087 Mon Sep 17 00:00:00 2001
From: Glenn Washburn <development@efficientek.com>
Date: Thu, 3 Mar 2022 01:53:31 -0600
Subject: [PATCH] um: port_user: Allow setting path to port-helper using
UML_PORT_HELPER envvar
This is useful when the uml-utilities user-space package has not been
installed by the administrator and an unprivileged user wants to be able to
telnet into a UML instance. The user can install the port-helper binary to
a writable path and set UML_PORT_HELPER. Fallback to using hardcoded path to
port-helper if environment variable is not set.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
arch/um/drivers/port_user.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/um/drivers/port_user.c b/arch/um/drivers/port_user.c
index 0625aa42041d..3e32351dadad 100644
--- a/arch/um/drivers/port_user.c
+++ b/arch/um/drivers/port_user.c
@@ -167,10 +167,14 @@ static void port_pre_exec(void *arg)
int port_connection(int fd, int *socket, int *pid_out)
{
int new, err;
+ char *env;
char *argv[] = { "in.telnetd", "-L",
OS_LIB_PATH "/uml/port-helper", NULL };
struct port_pre_exec_data data;
+ if ((env = getenv("UML_PORT_HELPER")))
+ argv[2] = env;
+
new = accept(fd, NULL, 0);
if (new < 0)
return -errno;